Last night was terrible again

, and really the nights have been very similar for a good 1-2 weeks so I think a pattern is setting in here.
I need a plan. Rightly or wrongly I can't carry on like this. I'm exhausted. Now, I'm not saying that as in 'I need my ridiculously small baby to sleep more so I can have a full nights sleep', but I am very concerned that I am placing him at risk with the current situation

.
My DH can't help an awful lot. He offers to, he isn't being an a**, but he is a surgeon and operates almost daily currently. He takes his turn at the weekend, and he also deals with our DD who still suffers night terrors from time to time. But it simply isn't fair on his patients to have him up have the night either.
Last night he was asleep at 7.15pm (ended up rocked by DH as he woke when I put him down and failed to resettle). Woke at 9.30pm refluxing. I picked him up and resettled and put him back in his bed. Then woke at 11.30pm hungry. Took 5oz and went back to sleep in his cot. Then woke at 1.30am refluxing, I resettled but fell asleep with him in my arms and I woke at 3.15am

. I put him in his cot and he woke up.... Decided he was hungry and I fed him 5oz and he cried again and I had to make another 1oz. Asleep on me and then back into cot. Woke at 5.30am refluxing, settled on me and again I fell asleep holding him and we woke at 6.45am.
It's the falling asleep holding him that I have a major issue with (obviously!!!). I recognise that reflux wakes him, but equally he has no IS skills and ends up in arms, and then I am exhausted and fall asleep.
What should I do.... I recently increased his reflux meds with no joy and we have a paeds appt in 1.5 weeks to try and address that side.
Should I try to get some IS skills? Or just be very focused on getting him back into his cot even though I have rocked/ cuddled to sleep?
Side/back/tummy makes no difference.
He has a dummy but I am wondering if I should stop using it? He rarely falls asleep with it. Tends to suck into a light sleep but then wake rather than ever enter a deep sleep. And he turns his head to the side so it always falls out. He also often refuses to even take it in the first place.
I know I can't fix his routine or naps or anything until his reflux clears.... But surely there is a better option than this

?
Incidentally yesterday his naps were fine... 30mins am, 1.5hrs next, then 2hrs... But I held him for all of the longer naps and then I feel awful for my other 2 kids.